fix a couple flaky nonnull attribute ubsan warnings

src/core/SkRecordDraw.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkLayerInfo.h"
 #include "SkRecordDraw.h"
 #include "SkPatchUtils.h"
@@ skipping 675 matching lines @@
                 dst.fPaint = new SkPaint(*src.fPaint);
             }
             dst.fSaveLayerOpID = src.fSaveLayerOpID;
             dst.fRestoreOpID = src.fRestoreOpID;
             dst.fHasNestedLayers = src.fHasNestedLayers;
             dst.fIsNested = fSaveLayersInStack > 0 || src.fIsNested;
 
             // Store 'saveLayer ops from enclosing picture' + drawPict op + 'ops from sub-picture'
             dst.fKeySize = fSaveLayerOpStack.count() + src.fKeySize + 1;
             dst.fKey = new int[dst.fKeySize];
-            memcpy(dst.fKey, fSaveLayerOpStack.begin(), fSaveLayerOpStack.count() * sizeof(int));
+            sk_careful_memcpy(dst.fKey, fSaveLayerOpStack.begin(),
+                              fSaveLayerOpStack.count() * sizeof(int));
             dst.fKey[fSaveLayerOpStack.count()] = fFillBounds.currentOp();
             memcpy(&dst.fKey[fSaveLayerOpStack.count()+1], src.fKey, src.fKeySize * sizeof(int));
         }
     }
 
     void trackSaveLayers(const DrawPicture& dp) {
         this->trackSaveLayersForPicture(dp.picture, dp.paint);
     }
 
     void trackSaveLayers(const DrawDrawable& dp) {
@@ skipping 93 matching lines @@
 void SkRecordComputeLayers(const SkRect& cullRect, const SkRecord& record, SkRect bounds[],
                            const SkBigPicture::SnapshotArray* pictList, SkLayerInfo* data) {
     SkRecords::CollectLayers visitor(cullRect, record, bounds, pictList, data);
     for (int curOp = 0; curOp < record.count(); curOp++) {
         visitor.setCurrentOp(curOp);
         record.visit<void>(curOp, visitor);
     }
     visitor.cleanUp();
 }